Ancient tooth enamel proteomes to help understand post mortem protein degradation over millions of years

The tooth enamel proteome is enzymatically broken down during development, which leads to a heterogenous distribution of remaining peptides of a protein sequence in a grown individual's enamelome. After death of the organism, the heterogeneous distribution of remaining peptides may be enhanced, as the proteome further degrades. The pattern of this degradation is poorly understood, but it might happen at different rates depending on the site within the protein sequence, due to different chemical properties of the peptides and their interaction with the environment. To learn more about this process, we recovered six ancient enamel proteomes from Equidae and Proboscidea fossils from Spain. The fossils span an age range of <100 ka to 11.6 Ma.